A Three-Dimensional (42.84)-lvt Topology and a Two-Dimensional Brick-Wall Network: Two Pillared Supramolecular Isomers Exploring the Use of l-Cysteic Acid to Engineer Porous Frameworks

Abstract

The preparations via variation of the reactive conditions of the same metal-to-ligand ratios of Co(NO3)2·6H2O with mixed l-cysteic acid (H2cys) and 4,4′-bipyridine (bpy) ligands gave rise to two interesting pillared supramolecular isomers: {[Co2(cys)2(bpy)2(H2O)2]·3H2O}n (1) and {[Co2(cys)2(bpy)(H2O)4](bpy)·H2O}n (2), which have the same formula but distinct solid phases. In the two complexes, Co(II) centers are chelated and bridged by different μ2-cys bridges to form a one-dimensional (1D) 41 helical chain and a 1D zigzag chain, respectively. The two chains are further linked by bpy pillars into a novel three-dimensional (42.84)-lvt structrue (1) and a two-dimensional brick-wall structure (2), respectively. The magnetic behavior of compounds 1 and 2 was studied, and it indicated the existence of small antiferromagnetic coupling. Best fit parameters for 1: J = −0.14 K with R = 4.77 × 10−4; for 2, J = −0.64 K with R = 3.62 × 10−4.